Can you use a variac when prototyping on a breadboard?

[jlmoon]

Judging by the OP's non-participation in the thread he created he may not have taken everyone's advice and is now 6 feet under.

Oh No!!!  Let's hope not!

[corrado33]

Not to hijack the thread, but do the same warnings apply for DC variacs? We have both DC and AC varieties in our lab and I use the DC ones for relatively low power devices often.

[IanB]

Not to hijack the thread, but do the same warnings apply for DC variacs? We have both DC and AC varieties in our lab and I use the DC ones for relatively low power devices often.

Well a variac is a variable transformer--usually an autotransformer. Variable because it has a continuously adjustable tap.

Since a transformer is by definition an AC device, can you be more specific about what a "DC variac" is in your lab?

[corrado33]

Our "DC" variac looks just like an AC variac but it only has two banana jacks for outputs. It outputs DC voltage, so I'm assuming it simply has a rectifier and some smoothing caps inside. I guess I could take it apart really quick if I wanted to.

EDIT: Our "DC" variacs are simply AC variacs (obviously) with a single high power rectifier. (MDA2504) Now I really want to measure the ripple on them. I have a sneaky suspicion that these variacs are homebrew (lab-brew?) jobs.

[Wim_L]

It is interesting to see that the isolated variacs are so uncommon in most places. For me it's the other way round, I have hardly ever seen a non-isolated one. You would find one of those isolated beasties in nearly every self respecting electronics workshop in Germany, even our local Ebay is flooded with them. I've got a 500W unit in my home lab and we use a ~1kW unit at work.
A really useful piece of equipment.
Maybe "isolated variac" is the wrong term in English?

You may find most of the modern ones really are 1:1 isolated mains transformers, followed by a normal variac. Still, functionally equivalent to an isolated variac, though likely a bit heavier (two cores).